1. Field of the Invention
This invention relates, in general, to motor vehicle fuel systems and, more specifically, to vapor and/or fuel seals for motor vehicle fuel systems.
2. Description of the Prior Art
In order to operate motor vehicles, such as automobiles, boats, airplanes, trucks, etc., fuel, such as gasoline, diesel, kerosene, etc., is required to operate the engines of such devices. Typically, the fuel is introduced into a tank within such vehicles from a supply reservoir through a dispensing nozzle. The fuel is introduced into the vehicle fuel tank in a liquid state but produces vapors at ambient temperatures and may also overflow through the filler tube if the tank is overfilled.
It is known that the vapors introduced into the atmosphere during the transfer of such fuels from the storage tank to the tank within such vehicles contributes to pollution of the atmosphere and, also, may cause harmful effects to the person dispensing the fuel through inhalation of the fuel vapors. In addition, combustible fuels are highly inflammable and may be easily ignited if brought into contact with a flame or hot surface.
Efforts have been made to prevent the discharge of such vapors or fuel into the atmosphere by providing a seal between the dispensing nozzle from the storage tank and the filler tube in the vehicle. Typically, such sealing means are in the form of a flexible cap attached to the dispensing nozzle which covers the end of the filler tube on the vehicle. While reducing the amount of vapors introduced into the atmosphere during the fuel transfer process, such previously devised sealing methods have not provided complete sealing of the filler tube such that significant amounts of fuel vapors still escape into the atmosphere. Furthermore, such sealing means do not prevent the escape of liquid fuel from the filler tube if the tank is inadvertantly overfilled or filled at too fast a rate.
It is also known to provide vapor seals for such fluid transfer processes as disclosed in U.S. Pat. No. 3,903,942. In this device, an adaptor is mounted within the filler tube on the vehicle which expands to sealingly receive the discharge end of the dispensing nozzle thereby preventing the escape of vapors from the vehicle tank during the fuel transfer process. However, this adaptor is provided with open inlet and outlet ends such that when the adaptor is not being used for the injection of fuel into the tank, the passage between the inlet and outlets is open thereby allowing the escape of vapors from the vehicle tank to the atmosphere when the filler tube cap is removed.
Thus, it would be desirable to provide a vapor/fuel seal for a vehicle fuel tank filler tube which completely seals the inlet to the filler tube during use of the vehicle and, provides a seal when a dispensing nozzle from a storage tank is introduced into the filler tube to add additional quantities of fuel into the vehicle fuel tank. It would also be desirable to provide a vapor/fuel seal for a fuel tank filler tube which may be easily installed on new and existing vehicles to provide the desired vapor and fuel sealing features described above.